Galvanometer



Oct. 29, 1946, c. M. HATHAWAY GALVANOMETER Filed Sept. 25, 1944 INVENTOR.

l atented Get. 29 1946 QFFlCE GALVANOMETER Claude M. Hathaway, Denver, (3010., assignor to Hathaway Instrument Company, a corporation of Colorado Application September 25, 1944, Serial No. 555,686

6 Claims.

The present invention relates to galvanometers, and more particularly to a polyphase watt galvanometer.

In investigations in the power transmission field it is not uncommon to operate with threephase circuits and frequently it would be desirable to obtain a three-phase Or polyphase watt galvanometer. In such galvanometers, the stationary field coils are used as current coilsand the moving field coils are used as potential coils. The torque exerted by each potential coil is proportional to the product of the current in the field coil and the current in the potential coil] Of course it would be highly desirable to provide a polyphase galvanometer which is relatively compact and which is economical to manufacture. In accordance with the present invention this is accomplished by the use of a cell block which is. readily machined and assembled. Further in accordance with the present invention such structure may be formed so as to be relatively compact.

It, therefore, is an object of the present invention to provide an improved, compact polyphase galvanometer.

It is another object of the present invention to provide an improved polyphase galvanometer cell construction.

Other and further objects of the present invention subsequently will become apparent by reference to the following description taken in connection with the accompanying drawing wherein Figure 1 is a front view of a three-phase galvanometer constructed in accordance with the present invention;

Figure 2 is a side view partially broken away of the galvanometer shown in Figure 1;

Figure 3 is a side view of a portion of the front plate of the galvanometer and the galvanometer element; and

Figure 4 is a rear view of the device shown in Figure 3.

Referring to the drawing it will be seen that in Figures 1 and 2 there is shown a three-phase galvanometer constructed in accordance with the present invention which has a base H provided with trunnions 12 for supporting the forward end of a subbase [3. The rear of the subbase I3 is provided with an adjusting screw member I l bearing against the base II. A suitable tension spring arrangement is mounted within a housing 15 so as to bias the rear end of thesubbase l3 toward the base Ii. The adjusting screw arrangement l4 which is of conventional type well known in the art is used to raise or lower the body of the galvanometer so as to position the galvanometer tracer on the record medium. In order to provide lateral displacement of the tracer there is provided an adjusting member it con nected to alever i'i directly beneath the subbase is having an upwardly extending pin 18 adapted to engage the bottom of the body of the galvanometer cell block. The galvanometer cell block is pivotally supported for angular displacement by the screw bearing member 19. The apparatus thus far described is well known in the art and hence will not be shown or described in further detail since it does not constitute a part of the present invention. 7 g j Suitably secured to the subbase i3 is a galvanometer cell formed of two similar side members 2i and 22, a rear cover 23 and a front cover it. The two side members 2! and 22 are formed of two blocks of metal held together by dowel pins 26 and 21. Extending from the front of the two side members 21 and 22 to aplane closely adjacent 22 is an elongated aperture 28 formed by two similar complementary recesses in these two members 2| and 22. The recess 28 therefore extends from the front surface of the two members 2| and 22 to a plane formed by the inner wall 29 seen in the cut-away portion of Figure 2. From the wall 29 to the rear of the side block members 2| and 22, these members are machined so as to provide a chamber having shelves formed therein for supporting a plurality of partitions forming compartments each arranged to contain an electromagnet. Since both the members 2! and 22 have similar inner walls, only the wall for the member 2! will be described. The wall BI ture of the electro-magnets. In between the re' cesses smaller recesses 35 and 36 are provided for receiving partitions 38 and 39 seen in Figure 2. The grooves or recesses 32 to 3% support magnetic core members M to G3- which are provided with coils or windings 44 to 46 respectively. The side members 2i and 22 when mounted togetherare provided with a generally circular opening ll at the top to accommodate the inside terminals'of a plurality of binding posts 48 supported upon a suitable insulating plate member 99. The inner terminals of the binding posts 48 are suitably connected to the windings M to 45. A gasket M is interposed between the side members 2| and 22 and the back plate 23 which is retained in position by suitable fastening means or screws 52. The front plate 24 is provided with a gasket" 53,

3 and the plate is retained in position by suitable screws 54. The front plate 24 is provided at its inner surface with a support post 55 for holding in position one end of a multiple galvanometer assembly comprising the coils 56, 51, and 58. The other end of this assembly is retained in position by suitable adjustable apparatus contained within a housing 59. The housing 59 also serves as a filler opening through which oil may be supplied to fill the interior of the cell block. lhe front panel 24 is provided with four binding posts 5| so as to provide individual connections to one terminal of each of the coils 5G to 58 and to provide a common return connection. This arrangement of connections is clearly visible in Figure 4. The front panel 24 also supports a lens holder 62 secured in position by fastening means 63 so as to be in proper position relative to a reflecting mirror 64 carried by the multiple coil galvanometer element. By arranging the front cover 24 so as to carry the galvanometer element comprising the coils 56 to 58, the binding posts 6! which provide connections thereto, and the lens holder 62,.it will be appreciated that it is relatively easy to properly assemble the galvanometer cell during manufacture, and to disassemble the cell in the event that it is necessary to make repairs. The entire structure is comparatively compact and provides a polyphase watt galvanometer suitable for use in a multiple element oscillograph.

While for the purpose of describing and illustrating the present invention, a preferred embodiment has been shown in the drawing, it is to be understood that such variations are contemplated in the structure as may be commensurate n with the spirit and scope of theinvention set forth in the appended claims.

This invention is hereby claimed as follows:

, v1. A cell for a galvanometer comprising a block of metal formed of two similar pieces so that when assembled said block has a recess extending from the backof said block to a plane adjacent the front of said block, said recess having stepped sides to form a plurality of shelves for supporting core members, a rear panel for said block for closingoneend of said recess, a front panel for closing the other end of said recess, and means mounted on said front panel for supporting moving coil members.

2. A cell for a galvanometer comprising a block of metal formed of two similar pieces, said block when assembled having a recess extending from the back of said block to the front of said block, said recess having stepped sides to form a plurality of shelves for supporting a plurality of magnetic core members, a rearcover for said block for closing the rear of said recess, a front cover for closing the other of said recesses, means mounted on said front cover for'supporting a moving coil support member having thereon a plurality of moving coils for cooperation with said plurality of magnetic core members, and terminals mounted on said front cover for connection to said moving coils. I

3. A cell for a polyphase galvanometer comprising a block of metal having a recess-extending-from the back of said block to a plane adjacent the front of said block, said recess having stepped sides to form a plurality ofshelves, a plurality of magnetic core members mounted on said shelves and each provided with a concentrated flux magnetic gap, an elongated recess extending from the front of said block to said first mentioned recess in the proximity of said magnetic gaps, a rear cover for said block, a front cover for said block, said front cover having mounted thereon means for supporting on a common support member, a plurality of moving coils each arranged for cooperation with one of said magnetic core members, a plurality of terminals mounted on said front cover member for connection to said moving coils, and a plurality of magnetic baffle sheet members mounted on said shelves between said magnetic cores.

4. A cell for a polyphase galvanometer comprising a block of metal having a recess extending from the back of said block to a plane adjacent the front of said block, said recess having stepped sides to form-a plurality of shelves, a plurality of magnetic core members mounted on said shelves and each provided with a concentrated flux magnetic gap, an elongated recess extending from the front of said block to said first mentioned recess in alignment with said magnetic gaps, a rear cover for said block, a front cover for said block, said front coverhaving mounted thereon means for supporting on a common sup port member a plurality of moving coils each arranged for cooperation with one of said magnetic core members, a plurality of terminals mounted on said front cover member for connection to said moving coils, and means mounted on said front cover for filling said cell with oil.

5. Acell for a polyphase galvanom-eter com-. prising a block of metal having a recess extending from the back of said block to a plane adjacent the front of said block, said recess having stepped sides to form a plurality of shelves, a plurality of magnetic core members mounted on said shelves and each provided with a concentrated flux magnetic gap, an elongated recess extending from the front of said block to said first mentioned recess for access to said magnetic gaps, a, rear cover for said block, a front cover for said block, said front cover having mounted thereon means for supporting on a common support member a plurality of moving coils each ar-. ranged for cooperation with the magnetic gap of one of said magnetic core members, a plurality of terminals mounted on said front cover member for connection to said moving coils, and means mounted on the top 'of said cell for electrical connection with said coils.

6. A polyphase galvanometer comprising a block of metal formed of two similar pieces, said block when assembled having a recess extending from the back to a plane adjacent the front of said block, said recess having stepped sides to form a plurality of shelves, aplurality of magnetic core members each provided with an energizing coil, said magnetic core members being positioned on said shelves, a plurality of magnetic baflle members interposed between said magnetic cores and supported by certain of said shelves, said block having an elongated recess extending from the front to said first mentioned recess for access to said magnetic cores, a rear panelfor closing said first recess, a front panel for c10sing the other'recess, a plurality of moving coils mounted on a common support member, said support memberbeing positioned on said front paneLeach moving coil being associated Witha different magnetic core member, terminals mounted on said front panel for connection to said moving coils, a mirror mounted on said moving coil support member, means mounted on the top of said block for electrical connection with said energizing coils of said magnetic core mem-'- bers, and means mounted on-said front panel whereby said block may be filled with oil.-

CLAUDE M. HATHAWAY. 

